HIV AIDS remains a major health crisis among African American men who have sex with men (AA MSM). In a recent large-scale HIV seroprevalence survey, prevalence rates were highest among AA MSM (28%), compared to 16% among MSM of all other ethnicities. This is a health disparity that has been replicated in many different studies since the start of the AIDS epidemic. Given the scale of the HIV epidemic among AA MSM, we cannot prevent the ongoing spread of HIV in the United States until we find ways to field effective HIV prevention programs for AA MSM. Combination prevention approaches to HIV/AIDS offer considerable promise to achieve this goal by addressing some of the high risk contexts that increase transmission risk among AA MSM. However, our ability to design effective combination prevention approaches to lower HIV transmission risk among AA MSM depends on achieving a clear epidemiological understanding of both barriers and facilitators to HIV testing, receiving reactive test results for men who are HIV positive and timel access to medical care if HIV positive. Unfortunately, our ability to explain HIV testing and health care access behaviors among AA MSM is currently limited due to the difficulties of recruiting sufficiently large samples of AA MSM who are delaying access to HIV prevention and care services. These shortcomings hamper our ability to draw effective conclusions about targeted prevention efforts for AA MSM, including most fundamentally an informed evidence base upon which combination prevention strategies must be built. Syndemics theory, which examines the effects and interactions among multiple psychosocial health conditions (i.e. substance abuse, depression, violence victimization) associated with increased risks within marginalized and vulnerable populations provides an important theoretical framework to examining these behaviors, especially since it encompasses both vulnerabilities and resiliencies in high risk populations. This application proposes to address this situation by collecting data from a large scale sample of AA MSM (N=6000) to: 1. Measure the prevalence and identify syndemic associations of uptake of HIV testing among AA MSM 2. Measure the prevalence and identify syndemic associations of unknown HIV seropositivity among AA MSM 3. Measure the prevalence and identify syndemic associations of timely access to care among HIV+ AA MSM By partnering with well-established community groups to recruit large samples of vulnerable men, we will be in a position to characterize the barriers and facilitators to the essential buildig blocks of combination prevention approaches and so provide crucial information for developing effective programs to lower HIV transmission among AA MSM.